1. Field of the Invention
The present invention relates to a device for reproducing printing reproductions with very accurately controlled color components.
2. Description of the Prior Art
Prior art devices such as shown in German OS 24 45 651 discloses a device in which a raster scanner scans a colored picture as, for example, a color slide or finished color separated components as well and supplies a set of color component signals which are subjected to a color correction and supplied for checking through a printing reproduction computer to a display unit. The color component signals represent the color dosage values for the individual printing colors such as magenta, cyan, yellow and black and are to be corrected on the display unit using visual checking in the apparatus. So as to provide on the display unit the color impressions which are produced by the picture are printed with the corrected color component signals with the aid of the corresponding color chromatic components and the print reproduction computer is provided between the correction stage and the display unit with the computer taking into consideration the fixed parameters of the respecting processes in producing the display. In this apparatus the correction is undertaken and made visible in selected local areas. The corresponding color component signals are measured and are made assessable to a person skilled in the art to rework by hand the selected local areas of the color component slides or plates. These corrections are performed by etching or by photographic exposure with corresponding masks.
Such apparatus has the advantage that the correction is made visible but has the disadvantage that the actual correction of the color chromatic components must be performed by hand which is time consuming and does not assure that the corrections in the color chromatic component separations exactly correspond to the corrections appearing on the display unit since such corrections depend exclusively upon the skill of the craftsman making corrections.
Other devices are known which produce corrected color component separations automatically but where the setting of the correction must be performed manually specifically by means of densitometric measurements of various picture dot image points of the original and by the subsequent evaluation by a craftsman who must then manually set the color correction regulator. Such devices have the disadvantage that the correction also depends on the skill of the operator making the corrections and cannot be checked until the finished color components are the finished printed product is available. Equipping such devices with a display unit could be accomplished, however, because of a peculiarity of these devices, this cannot be realized or requires a very large expenditure for obtaining a suitable memory since the data which are supplied by a drum scanner in such a device spiral scanner or a scanner with intermittent feed are not suitable for producing a stationary picture because each point is scanned only once and controls a drum recording device on line.